// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/renderer/pepper/pepper_in_process_router.h"

#include "base/bind.h"
#include "base/location.h"
#include "base/single_thread_task_runner.h"
#include "base/threading/thread_task_runner_handle.h"
#include "content/public/renderer/render_thread.h"
#include "content/renderer/pepper/renderer_ppapi_host_impl.h"
#include "content/renderer/render_frame_impl.h"
#include "ipc/ipc_message.h"
#include "ipc/ipc_sender.h"
#include "ppapi/proxy/ppapi_messages.h"
#include "ppapi/shared_impl/ppapi_globals.h"
#include "ppapi/shared_impl/resource_tracker.h"

using ppapi::UnpackMessage;

namespace content {

class PepperInProcessRouter::Channel : public IPC::Sender {
public:
    Channel(const base::Callback<bool(IPC::Message*)>& callback)
        : callback_(callback)
    {
    }

    ~Channel() override { }

    bool Send(IPC::Message* message) override { return callback_.Run(message); }

private:
    base::Callback<bool(IPC::Message*)> callback_;
};

PepperInProcessRouter::PepperInProcessRouter(RendererPpapiHostImpl* host_impl)
    : host_impl_(host_impl)
    , pending_message_id_(0)
    , reply_result_(false)
    , weak_factory_(this)
{
    browser_channel_.reset(new Channel(base::Bind(
        &PepperInProcessRouter::SendToBrowser, base::Unretained(this))));
    host_to_plugin_router_.reset(new Channel(base::Bind(
        &PepperInProcessRouter::SendToPlugin, base::Unretained(this))));
    plugin_to_host_router_.reset(new Channel(
        base::Bind(&PepperInProcessRouter::SendToHost, base::Unretained(this))));
}

PepperInProcessRouter::~PepperInProcessRouter() { }

IPC::Sender* PepperInProcessRouter::GetPluginToRendererSender()
{
    return plugin_to_host_router_.get();
}

IPC::Sender* PepperInProcessRouter::GetRendererToPluginSender()
{
    return host_to_plugin_router_.get();
}

ppapi::proxy::Connection PepperInProcessRouter::GetPluginConnection(
    PP_Instance instance)
{
    int routing_id = 0;
    RenderFrame* frame = host_impl_->GetRenderFrameForInstance(instance);
    if (frame)
        routing_id = frame->GetRoutingID();
    return ppapi::proxy::Connection(
        browser_channel_.get(), plugin_to_host_router_.get(), routing_id);
}

// static
bool PepperInProcessRouter::OnPluginMsgReceived(const IPC::Message& msg)
{
    // Emulate the proxy by dispatching the relevant message here.
    ppapi::proxy::ResourceMessageReplyParams reply_params;
    IPC::Message nested_msg;

    if (msg.type() == PpapiPluginMsg_ResourceReply::ID) {
        // Resource reply from the renderer (no routing id).
        if (!UnpackMessage<PpapiPluginMsg_ResourceReply>(
                msg, &reply_params, &nested_msg)) {
            NOTREACHED();
            return false;
        }
    } else if (msg.type() == PpapiHostMsg_InProcessResourceReply::ID) {
        // Resource reply from the browser (has a routing id).
        if (!UnpackMessage<PpapiHostMsg_InProcessResourceReply>(
                msg, &reply_params, &nested_msg)) {
            NOTREACHED();
            return false;
        }
    } else {
        return false;
    }
    ppapi::Resource* resource = ppapi::PpapiGlobals::Get()->GetResourceTracker()->GetResource(
        reply_params.pp_resource());
    // If the resource doesn't exist, it may have been destroyed so just ignore
    // the message.
    if (resource)
        resource->OnReplyReceived(reply_params, nested_msg);
    return true;
}

bool PepperInProcessRouter::SendToHost(IPC::Message* msg)
{
    std::unique_ptr<IPC::Message> message(msg);

    if (!message->is_sync()) {
        // If this is a resource destroyed message, post a task to dispatch it.
        // Dispatching it synchronously can cause the host to re-enter the proxy
        // code while we're still in the resource destructor, leading to a crash.
        // http://crbug.com/276368.
        // This won't cause message reordering problems because the resource
        // destroyed message is always the last one sent for a resource.
        if (message->type() == PpapiHostMsg_ResourceDestroyed::ID) {
            base::ThreadTaskRunnerHandle::Get()->PostTask(
                FROM_HERE, base::Bind(&PepperInProcessRouter::DispatchHostMsg, weak_factory_.GetWeakPtr(), base::Owned(message.release())));
            return true;
        } else {
            bool result = host_impl_->GetPpapiHost()->OnMessageReceived(*message);
            DCHECK(result) << "The message was not handled by the host.";
            return true;
        }
    }

    pending_message_id_ = IPC::SyncMessage::GetMessageId(*message);
    reply_deserializer_.reset(
        static_cast<IPC::SyncMessage*>(message.get())->GetReplyDeserializer());
    reply_result_ = false;

    bool result = host_impl_->GetPpapiHost()->OnMessageReceived(*message);
    DCHECK(result) << "The message was not handled by the host.";

    pending_message_id_ = 0;
    reply_deserializer_.reset(NULL);
    return reply_result_;
}

bool PepperInProcessRouter::SendToPlugin(IPC::Message* msg)
{
    std::unique_ptr<IPC::Message> message(msg);
    CHECK(!msg->is_sync());
    if (IPC::SyncMessage::IsMessageReplyTo(*message, pending_message_id_)) {
        if (!msg->is_reply_error())
            reply_result_ = reply_deserializer_->SerializeOutputParameters(*message);
    } else {
        CHECK(!pending_message_id_);
        // Dispatch plugin messages from the message loop.
        base::ThreadTaskRunnerHandle::Get()->PostTask(
            FROM_HERE,
            base::Bind(&PepperInProcessRouter::DispatchPluginMsg,
                weak_factory_.GetWeakPtr(), base::Owned(message.release())));
    }
    return true;
}

void PepperInProcessRouter::DispatchHostMsg(IPC::Message* msg)
{
    bool handled = host_impl_->GetPpapiHost()->OnMessageReceived(*msg);
    DCHECK(handled);
}

void PepperInProcessRouter::DispatchPluginMsg(IPC::Message* msg)
{
    bool handled = OnPluginMsgReceived(*msg);
    DCHECK(handled);
}

bool PepperInProcessRouter::SendToBrowser(IPC::Message* msg)
{
    return RenderThread::Get()->Send(msg);
}

} // namespace content
